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3COM CORPORATION

COURIER 1200

Modem Type

Data (synchronous/asynchronous)

Maximum Data Rate

1200bps

Data Bus

External

Data Modulation Protocol

Bell 103A/212A

CONNECTIONS

Purpose

Location

Purpose

Location

Line out

CN2

DC power

CN4

Line in

CN1

Power switch

SW1

RS-232/422

CN3

   

DTR SIGNAL

Setting

SW2/1

» On

DTR forced high

Off

DTR normal

RESULT CODES

Setting

SW2/2

» Off

Verbal result codes enabled

On

Numeric result codes enabled

RESULT CODES DISPLAY

Setting

SW2/3

» On

Display enabled

Off

Display disabled

 

ECHO COMMANDS DISPLAY

Setting

SW2/4

» Off

Local echo enabled

On

Local echo disabled

AUTO ANSWER

Setting

SW2/5

» On

Modem does not answer on first ring

Off

Modem answers on first ring

CARRIER DETECT

Setting

SW2/6

Off

CD normal

» On

CD forced high

MULTILINE PHONE INSTALLATION

Setting

SW2/7

» Off

Single phone connected

On

Multiple phones connected

AT COMMAND SET

Setting

SW2/8

» On

AT command set recognized

Off

AT command set disabled

ESCAPE CODE

Setting

SW2/9

» On

Go to command mode and display OK result code when escape character is received

Off

Disconnect, go to command mode and display NO CARRIER when escape character is received

DTR RESET

Setting

SW2/10

» Off

DTR normal

On

Reset 50ms after receiving DTR low signal.

TX/RX PIN ASSIGNMENT

Setting

SW3

» Off

Normal operation

On

Reverse TX/RX pin assignments

 

DIAGNOSTIC LED(S)

LED

Color

Status

Condition

HS

Red

On

Modem is operating at 4800bps or faster

HS

Red

Off

Modem is operating at slower than 4800bps

AA

Red

On

Auto-answer enabled

AA

Red

Off

Auto-answer disabled

CD

Red

On

Carrier signal detected

CD

Red

Off

Carrier signal not detected

OH

Red

On

Modem is off-hook

OH

Red

Off

Modem is on-hook

RD

Red

On

Modem is receiving data

RD

Red

Off

Modem is not receiving data

TD

Red

On

Modem is transmitting data

TD

Red

Off

Modem is not transmitting data

TR

Red

On

DTR signal is high

TR

Red

Off

DTR signal is low

MR

Red

On

Power is on

MR

Red

Off

Power is off

AL

Red

On

Analog loopback self test mode

AL

Red

Off

Normal operation

Proprietary AT Command Set

See document V1254 for a full command summary.